Day of the Week Calculator
Find what day of the week any date falls on
Enter Date
Day of the Week
About This Calculator
The Day of the Week Calculator helps you determine what day of the week a specific date falls on. It's useful for planning events, scheduling meetings, historical date research, and general date calculations.
This tool is essential for event planning, scheduling, and historical research. Simply enter any date (past, present, or future), and the calculator will instantly tell you what day of the week it falls on.
Formula & Calculation Method
The day of the week is calculated using various algorithms:
- Zeller's Congruence: A mathematical formula that calculates the day of the week for any date in the Gregorian calendar
- JavaScript Date Object: Uses built-in date functions to determine the day of the week
Zeller's Congruence Formula:
h = (q + ⌊(13(m+1))/5⌋ + K + ⌊K/4⌋ + ⌊J/4⌋ - 2J) mod 7
Where:
- h = day of the week (0 = Saturday, 1 = Sunday, 2 = Monday, ..., 6 = Friday)
- q = day of the month
- m = month (3 = March, 4 = April, ..., 14 = February)
- K = year of the century (year mod 100)
- J = zero-based century (⌊year/100⌋)
Note: This calculator uses JavaScript's built-in Date object, which handles leap years, month lengths, and calendar conversions automatically.
How to Use This Calculator
Frequently Asked Questions
What calendar does this calculator use?
This calculator uses the Gregorian calendar, which is the standard calendar used in most of the world today. It accounts for leap years and month length variations.
Can I find the day of the week for historical dates?
Yes, you can enter any date from year 1 onwards. However, for dates before the Gregorian calendar was adopted (1582), the results may not match historical records that used the Julian calendar.
How accurate is this calculator?
This calculator is highly accurate for dates in the Gregorian calendar. It properly handles leap years, including century years that are not leap years (e.g., 1900) and century years that are leap years (e.g., 2000).
What if I enter an invalid date?
The calculator will display an error message if you enter an invalid date. Make sure the date exists (e.g., February 30 is invalid) and is in a valid format.
NumCalculators Editorial Team
Multi-disciplinary Expert Team
The NumCalculators Editorial Team consists of subject matter experts across various fields who review and verify the accuracy of our calculators. Each calculator undergoes rigorous testing and validation before publication.